raise error when name is more than 32 when creating target group

moto/elbv2/exceptions.py

@@ -166,3 +166,11 @@ class DuplicatePriorityError(ELBClientError):
         super(DuplicatePriorityError, self).__init__(
             "ValidationError",
             "Priority '%s' was provided multiple times" % invalid_value)
+
+
+class InvalidTargetGroupNameError(ELBClientError):
+
+    def __init__(self, invalid_name):
+        super(InvalidTargetGroupNameError, self).__init__(
+            "ValidationError",
+            "Target group name '%s' cannot be longer than '32' characters" % invalid_name)

moto/elbv2/models.py

@@ -21,7 +21,8 @@ from .exceptions import (
     ActionTargetGroupNotFoundError,
     InvalidDescribeRulesRequest,
     RuleNotFoundError,
-    DuplicatePriorityError
+    DuplicatePriorityError,
+    InvalidTargetGroupNameError
 )
 
 
@@ -264,6 +265,8 @@ class ELBv2Backend(BaseBackend):
         return [rule]
 
     def create_target_group(self, name, **kwargs):
+        if len(name) > 32:
+            raise InvalidTargetGroupNameError(name)
         for target_group in self.target_groups.values():
             if target_group.name == name:
                 raise DuplicateTargetGroupName()